Changes in extreme temperatures and precipitation over pan-Arctic land driven by anthropogenic influences

In an increasingly warmer and wetter Arctic, the intensity and frequency of extreme climate events have risen, but there is still a lack of comprehensive reports of extreme events in the Arctic over the past few decades, and little is known about the anthropogenic influences on extreme events in the Arctic. In this study, we first show that the Coupled Model Intercomparison Project Phase 6 (CMIP6) models effectively capture the climatological patterns of extreme temperature and precipitation events. The multimodel ensemble mean (MME) results are better than those of most of the individual models. Then the long-term trends of simulations and reanalysis indicate that the pan-Arctic region experienced a significant increase in extreme warm events (intensity, frequency and duration) and extreme precipitation events and a significant decrease in extreme cold events (intensity, frequency and duration) during the period of 1960–2014. Finally, attribution analysis using regularized optimal fingerprinting (ROF) indicates that long-term changes in temperature and precipitation extremes across the pan-Arctic land are driven by anthropogenic impacts. Greenhouse gas (GHG) forcing is the primary contributor, accounting for 98 %–126 % of the trends across most extreme indices except for individual percentile-based indices. This effect is partially offset by anthropogenic aerosols (−18 %–0 %), while the influence of natural forcing is negligible. Our findings provide clear evidence that human activities are the primary driver of extreme temperature and precipitation over pan-Arctic land.